Maxima Function
gcd (p_1, p_2, x_1, ...)
Returns the greatest common divisor of p_1 and p_2.
The flag gcd determines which algorithm is employed.
Setting gcd to ez, subres, red, or spmod selects the ezgcd,
subresultant prs, reduced, or modular algorithm,
respectively. If gcd false then gcd (p_1, p_2, x) always returns 1
for all x. Many functions (e.g. ratsimp, factor, etc.) cause gcd's
to be taken implicitly. For homogeneous polynomials it is recommended
that gcd equal to subres be used. To take the gcd when an algebraic is
present, e.g., gcd (x^2 - 2*sqrt(2)*x + 2, x - sqrt(2)), algebraic must be
true and gcd must not be ez. subres is a new algorithm, and people
who have been using the red setting should probably change it to
subres.
The gcd flag, default: subres, if false will also prevent the greatest
common divisor from being taken when expressions are converted to canonical rational expression (CRE)
form. This will sometimes speed the calculation if gcds are not
required.